The NPCs help with everything but the boss. Again, we have set up the markers in front of them and then literally on top of them. Both times they did no damage to galakras.
Just tonight we were having problems with the boss and decided to tank exactly where Jaina spawns her Blizzard. Shortly after getting him in position she casted it and the adds went rushing in. According to our logs, they contributed more than 20% of the damage and this was by far our cleanest kill yet. It honestly boggles my mind why no strat videos recommend engaging the NPCs.